package cn.tedu.helloword;

import java.util.ArrayList;
import java.util.List;

public class TestLianXi {
    public static void main(String[] args) {
            StringBuffer sb =new StringBuffer("大家好!");
        System.out.println(sb);
        System.out.println(sb.append("我是程序员！"));
        System.out.println(sb.insert(6,"优秀的"));
        System.out.println(sb.replace(6,9,"牛牛的"));
        System.out.println(sb.substring(4,13));

    }


}
